The war against COVID is still being waged. While it isn’t going to end anytime soon, time and data have allowed us to learn more about long-term effects of the disease, such as long COVID.

Long COVID is a global health burden, with more than 200 symptoms of long COVID having been reported, including breathlessness, fatigue and brain fog, making it hard for people to return to normal employment or activities even months later.

Here is the latest research on long COVID, including prevention, detection and treatment.

Vaccines help protect against long COVID

People who are vaccinated can still experience the lingering debilitating symptoms that affect the heart, brain and respiratory system.

A study from the US of more than 13 million war veterans found that the COVID-19 vaccination reduced the risk of death by 34%, and reduced the risk of getting long COVID by 15%, compared to unvaccinated patients. The risk of contracting long COVID was also 17% higher among vaccinated immunocompromised people, compared to previously healthy vaccinated people.

“Vaccinations remain critically important in the fight against COVID-19,” says first author Dr Ziyad Al-Aly, from Washington University (US). “Vaccinations reduce the risk of hospitalisation and dying from COVID-19. But vaccines seem to only provide modest protection against long COVID. People recovering from breakthrough COVID-19 infection should continue to monitor their health and see a health-care provider if lingering symptoms make it difficult to carry out daily activities.”

Vaccines also helped to halve the prevalence of some of the more severe symptoms of long COVID, including respiratory illnesses (reduced by 49%) and blood-clotting disorders (56%).

“Now that we understand that COVID-19 can have lingering health consequences, even among the vaccinated, we need to move toward developing mitigation strategies that can be implemented for the longer term since it does not appear that COVID-19 is going away any time soon,” says Al-Aly. “We need to urgently develop and deploy additional layers of protection that could be sustainably implemented to reduce the risk of long COVID.”

The research has been published in Nature Medicine.

MRI finds lung abnormalities in long COVID patients

Long COVID can be difficult to detect, but with a special type of MRI scanner, lung abnormalities have been found in patients with long COVID, including those who haven’t been hospitalised with the illness. This findings have been published in Radiology.

“In a collaboration between the University of Oxford and the University of Sheffield, we have been able to identify abnormalities in the lungs of both hospitalised and non-hospitalised participants using a novel imaging technique, Hyperpolarized Xenon 129MRI, or Hp-XeMRI,” says senior author of the study, Dr Fergus Gleeson, from the University of Oxford/Oxford University Hospital NHS Trust. “These abnormalities are not apparent on conventional imaging, and in some individuals were detected up to a year after their initial COVID-19 infection.”

Non-hospitalised long COVID (NHLC) patients and post-hospitalised COVID-19 (PHC) patients all had symptoms of breathlessness. Participants were given a chest CT, the new Hp-XeMRI imaging test, pulmonary function tests, one-minute sit-to-stand tests and breathlessness questionnaires. The CT scans revealed normal to near-normal results for both NHLC and PHC, but the Hp-XeMRI was able to detect abnormalities in the lung alveoli, where gas exchange occurs.

“We saw that the ability of gas to transfer from the lungs into the blood stream was less in non-hospitalised patients in comparison to those hospitalised with COVID,” says Gleeson.

The Hp-XeMRI test results showed significant differences in mean red blood cell to tissue plasma ratios, indicating a difference in lung function. In long COVID patients, breathing pattern disorders are the most commonly identified and attributed to the cause of breathlessness, though there may be additional reasons for breathlessness that these imaging technologies have been unable to pick up.

“Using Hp-XeMRI may enable us to further understand the cause of breathlessness in long COVID patients, and ultimately lead to better treatments to improve this often-debilitating symptom,” says study co-author Dr James Grist from University of Oxford/Oxford University Hospital NHS Trust.

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Example of CT, proton, proton and RBC:TP imaging from post-hospitalised participants with different levels of severity of illness. Credit: Radiological Society of North America

Long COVID could have a significant mental component

In a US study by the National Institutes of Health (NIH) across 189 recovered COVID-19 patients, 55% of participants experienced persistent long COVID symptoms.

This included fatigue, respiratory discomfort, loss of smell, headache, insomnia, memory impairment, anxiety and difficulty concentrating.

But researchers could not find any physical evidence of persisting viral infection or damage to tissue or organs in these patients, indicating that there could be a significant mental component associated with long COVID.

These patients self-reported a worsening of physical and mental health, and a lower quality of life, compared to participants without long-COVID symptoms and control participants who did not contract COVID at all.

With a myriad of symptoms, and the absence of objective abnormalities, long COVID resembles illnesses such as chronic fatigue syndrome, post-infection syndrome, and mental health disorders such as depression and anxiety.

You can read more about this research in the Annals of Internal Medicine.



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